Basically this scam starts from your friend/s sharing a video entitled "This woman has a orgasm on a roller coaster". Clicking on it will bring you to a YouTube phishing site that requests for a verification code and survey. What it does is actually to obtain your answers to help them earn money, then possibly hacking into your account after you'd done the survey. Of course, it will replicate the link back into your Facebook wall, thereby completing the viral spread to your friends.
More details can be found via googling. Take care everyone!